Exemplary embodiments pertain to the art of slat-flap control levers for aircrafts and, more particularly, to a retention member monitoring system and method for such slat-flap control levers.
Aircraft slat and flap systems include slats and flaps that are extended and retracted at variable positions depending on the aircraft's take-off or landing situation to provide high lift to the aircraft at lower aircraft speeds. Actuation of the slats and flaps is provided in response to input from an aircraft operator. The input is made by movement of a slat-flap control lever. It is important to maintain the slat-flap control lever in a desired position to ensure desired positioning of the slats and flaps.
A typical slat-flap control lever design utilizes a detent pin and gating system to prevent the control lever from unintentional movement after it has been set. The detent pin extends out both sides of the control lever and the load share is split between both sides of the pin. Failure of one side of the pin is considered a dormant failure because the lever will operate normally without alerting the operator (e.g., pilot). Should both sides of the detent pin fail, the lever would be subject to unrestricted movement. Unrestricted movement could result in un-commanded slat-flap system motion if the lever was bumped or accidentally moved. Since a single-sided detent pin failure has been identified as a dormant failure, periodic inspections are required which must be scheduled and require aircraft downtime.